In modern automotive vehicles, subframes are widely used for isolating vibration and increasing connection strength of other relevant parts of the vehicles, such as engines, powertrains, suspension systems or the like. For example, a subframe is usually provided in an automotive vehicle. The subframe is attached to the vehicle body, and is mounted with a suspension system thereon. In this way, the suspension system is associated with the vehicle body such that less vibration can be transmitted from an engine of the vehicle or roads to the suspension system or a passenger compartment of the vehicle. Since the suspension system is connected indirectly with the vehicle body itself via the subframe, the suspension system can be more reliably secured relative to the vehicle body.
The subframe is usually made by sheet metal parts. In order to reduce the total weight of the vehicle, the subframe should be light. For example, aluminum alloy or titanium alloy or the like can be used to manufacture the subframe. Further, in order to enable the subframe to be lighter, the thickness of the sheet metal part of the subframe is designed to be as little as possible. However, if the sheet metal part of the subframe is too thin, the stiffness of the subframe itself will be insufficient to bear the suspension system and attach to the vehicle body. Therefore, it is desirable to find a way of reducing the weight of the subframe itself while enabling it to have sufficient stiffness.
Patent publication EP2165919 discloses a reinforced structure including a structural component (2) and a reinforcing part (4) that is arranged in a cavity of the structural component, wherein the reinforcing part (4) comprises a support part (5) and connection means (6) which can be a foamed material. However, this reference does not concern how to lighten and strengthen the subframe. Rather, this reference concerns how to optimize use of the activatable foamed material. Specifically, the optimization is achieved by using a lesser amount of the activatable foamed material at positions with high deformation than at positions with low deformation of the component.
Patent publication US20120315414 discloses a composite component made up of a shell at least locally and peripherally delimiting a space and also discloses a structural component with structural material being provided at least locally between the shell and the structural component. This reference does not concern how to lighten and strengthen the subframe either.
Patent publication WO2012140154 generally concerns how to reinforce attachment of a subframe to a mainframe of a vehicle. This reference does not concern how to lighten and strengthen the subframe itself.
As mentioned above, the subframe of the vehicle should be designed to have high stiffness and low weight such that the vehicle can run more fuel-efficiently and can be manufactured at lower costs. To this end, the subframe should be made by reducing use of sheet metal parts and by adding other alternative parts. However, it is difficult and unknown to determine how to reduce the use of sheet metal parts with maintaining the stiffness of the subframe.